1. Field of the Invention
The invention relates generally to horizontal coke oven batteries and more specifically to doors and door jambs used to seal the chambers of horizontal coke oven batteries.
2. Description of the Prior Art
One of the critical current problems in the production of coke from coal is the presence of pollution and contaminants escaping from coke oven batteries. Horizontal coke oven batteries are each comprised of a series of long narrow horizontal coking chambers. At each end of each chamber is a door, one being on the pusher side of the oven and one being on the coke side of the oven. When a charge of coal has been coked, both the pusher side door and the coke side door are removed by mechanical door machines. Then a pusher machine commences to push the coke from the pusher side through the coking chamber and out the coke side into a collecting device.
Once a coking chamber has been pushed and is empty, apparatus associated with the door machines is brought into operation to clean the seals on the door and the corresponding door jambs. Typically, the cleaning is done by scraping both the seals and the jambs to remove deposits of coal tar and other material which has built up thereon during the coking of the coal. If the buildup on the seals and jambs is not removed, the seals are substantially prevented from performing their function, that is, to prevent the escape of pollutants. But it is the escape of these pollutants which causes the problem in the first place. The pollutants carry with them, in their escape, coal tar and other material which builds up on the seals and jambs. This fact suggests that the state of the art is deficient in providing effective sealing apparatus. If the available sealing apparatus were efficient, no buildup would occur and thus there would be no need for cleaning and, consequently, no cleaning apparatus associated with the door machines.
Through the years many novel devices and systems have been suggested to cure the problem. Recently, the problem has been deemed urgent. Concern over pollution has become prominent in view of increasing governmental regulations agitated by proponents of counter-economic advancement. A proliferation of prior art has been published recently in the field. Yet the coke industry continues to admit that pollution escape from coke oven doors is the largest single uncured factor in pollution control problems in coke plants.
The current state of the art in the design of door-sealing means is directed at the use of knife-edged seals projected against flat-machined surfaces. Flexible springs are utilized to apply pressure to the seals when the door is in place. Double knife-edged seals are known wherein two parallel knife edges are applied to the flat-machined surface. The concept here seems to be, if one will not work, try two. It has even been suggested, in relation to the double knife-edged seals, that the space separating the two edges could be pressurized beyond the interior pressure of the coke oven. However, in practice, this suggestion has proved unworkable. The heat differential between the interior of the oven and the exterior causes some slight degree of warpage of the knife edge. The pressure differential rapidly disappears as this warpage occurs. Once the pressure equalizes the chamber between the two knife edges equalizes with the interior of the coke oven, the pollution commences to be expelled around the doors.
Forethinkers have viewed this problem and postulated that if you cannot pressurize the chamber between the double knife edges, perhaps it is possible to draw a vacuum on it, thus allowing the pollution to be sucked up and introduced back into the coke oven before it can escape to pollute. Preliminary tests have indicated that this approach is viable as a means of eliminating the pollution. However, the buildup on the seals on door jambs still remains as a problem, thus necessitating the seal and jamb cleaning apparatus associated with the door machines.